Mix flour, baking powder and salt.
Cream butter with shortening.
Gradually beat in sugar and continue beating until light and fluffy.
Add eggs, one at a time, beating thoroughly after each.
Stir in vanilla and chocolate.
Gradually add flour mixture, blending thoroughly after each addition.
Shape into balls, using 1/2 tablespoons for each.
Place 2 inches apart on greased baking sheets.
Using flat-bottom glass, buttered and dipped in granulated sugar, press cookies to 3-inch diameters.
Bake at 375° about 10 minutes.
Cool on racks.
Top with glaze.